Vapor-dispersing devices are well known and include a variety of devices for vaporizing a liquid such as a perfume or insecticide into the surrounding environment. For example, vapor-dispersing devices include electrical devices with resistive heater modules and/or fans for driving liquids into the vapor phase, passive devices that rely on pads, wicks, or combinations thereof having large surface area for evaporating liquids without energy input, and simple aerosol sprays that propel and disperse liquids into fine droplets that evaporate in the air. Vapor-dispersing devices that are electrically powered are very common in home and institutional settings around the world. These devices may comprise a bottle of volatile liquid and they may operate by heat to volatize the liquid. Most common of these devices are air fresheners wherein a porous plastic wick is in communication with a bottle of scented fragrance oil and wherein the wick, operating as both a liquid transfer means and evaporative member and is continuously saturated with the fragrance, is placed in close proximity to a resistive heater element that accelerates the evaporation of the liquid from the wick. Another common configuration for a household air freshener comprises a bottle of scented fragrance oil with a porous plastic wick positioned in front of a fan. In these devices the fan moves air across the wick and the scented air is expelled into the immediate environment. These devices exist in the marketplace, both house current powered (110 v/220 v, AC) and battery powered (1.5 v, 3 v, 9 v, etc., DC). Exemplary devices include the Glade® Plugins® Scented Oil and Plugins® Scented Oil Fan air freshener products from S.C. Johnson & Son, Inc., and the Mobil'Air® Portable Electric Diffuser air freshener from Reckitt Benckiser. More elaborate products include piezoelectric devices wherein the scented fragrance oil is wicked up from a reservoir onto a vibrating plate where it is expelled into very fine droplets that quickly evaporate. One such device is the battery operated Glade® Wisp® Scented Oil Fragrancer air freshener from S.C. Johnson & Son.
In spite of the fact that fan, heater, fan plus heater, and piezoelectric air fresheners have dominated the marketplace over the last decade or so, there remain many limitations to such electronic devices. Most problems relate to the fact that the wick is both the evaporation medium and the liquid transfer means and as the evaporation surface it either needs to be of a huge size (e.g., a thick fiber bundle) or heated by a proximate heating element. Invariably these devices slow down since the porous wicks clog with the less volatile ingredients and the spectrum of fragrance notes changes throughout the lifetime of the device, particularly if the wick is comprised of a fiber bundle and used in association with an aqueous fragrance solution containing a surfactant. In that instance, the large fiber wick will clog over time with the non-volatile surfactants and emulsifiers used to stabilize in the fragrance solution. In the heated example, the saturated heated wick continually leaves behind dark yellow, non-volatile base notes, and the wick clogs with no further new surfaces and unclogged pores left to assist in evaporation.
We have invented a unique way to circumvent these limitations by using a liquid transfer member and a moving evaporative member that are kept from constant contact with one another, and wherein the evaporative member is kept from complete saturation so that a continuous fresh surface is available for evaporation of volatile liquid. The way the present invention accomplishes this is by having a moveable piston that moves the evaporative member repeatedly into momentary contact with the end of the liquid transfer means with each stroke. By moving the evaporative surface and keeping it from full saturation, the evaporation of the liquid is more controlled and the distribution of the volatile components remains more constant throughout the evaporation of the liquid. The movement of the piston also serves as a bellow-means to expel the air treated with the volatile material and still residing in the device out into the environment.
Vapor-dispersing devices that contain pistons are extremely scant in the literature and are all based on movement of a piston to increase internal pressure within a reservoir to push liquid out. For example, U.S. Pat. No. 5,954,268 to Joshi, et al. and U.S. Pat. No. 5,776,561 to Lindauer both describe reservoirs that may be pressurized by depression of a piston and wherein the pressure forces liquid fragrance up a capillary tube and out onto an evaporative surface formed in the shape of a decorative flower.
U.S. Pat. No. 4,477,414 to Muramoto, et al. describes a piston operable device where depression of the piston forces liquid out through a capillary tube and onto an impregnation member where it evaporates. U.S. Pat. No. 6,923,383 to Joshi, et al. describes a device wherein a piston-actuated pressurization expels liquid through a restrictive opening. Lastly, piston actuated spray devices include the device described in U.S. Pat. No. 5,221,025 to Privas.
Devices that employ a bellows-type action to expel scented air include the devices described in U.S. Pat. No. 4,869,407 to Booth, et al.
None of these devices employ a moveable piston in a non-pressurized device for effecting the repeated touching of an evaporative member onto the end of a liquid transfer means such that volatile liquid is pulled from a reservoir and evaporated into the adjacent environment in a controlled manner.